its a dynasty 3.3. why doesn't the serpentine belt stay on on 1990 Dodge D250

this last summer i bought my granddaughter a 1990 dodge dynasty. we've put on three serpentine belts on and they keep coming off. can someone help me? from lorraine. crying in drayton nd

by in Drayton, ND on March 25, 2011
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1 answer 1 comment
ANSWER by , March 25, 2011
COMMENT by , March 25, 2011
i'm sorry, i guess i forgot to say we did that also. but thanks for a good answer.lorraine